Objective: Global racial variability in human development can lead to differences in size of fetal cardiac structures during gestation. Our objective is to establish normal reference ranges of fetal cardiac dimensions between 20 and 34 weeks from fetal echocardiograms recorded at a single center in China.
Methods: A prospective cross-sectional study was undertaken on single pregnancies with normal fetuses of varying gestational ages (GAs). A total of 4396 normal fetuses were divided into 15 groups from 20 to 34 weeks according to the GA. Measurements included the inner diameter of the fetal cardiac chambers and arteries, the aortic arch isthmus (AI), the descending aorta (DAO), the ductus arteriosus (DA), and the foramen ovale (FO). Measurements were statistically analyzed and regression analysis was applied to assess for correlation with GA.
Results: Normal reference values of fetal cardiovascular dimensions between 20 and 34 weeks were obtained from 4396 subjects at a single center in China. Measurements of fetal cardiac structures increase with advancing GA. It seems there is no difference in r values among linear, cubic, and quadratic model analyses (P > 0.05). However, the r values for the exponential models appear to be smaller than those of the other three models (P < 0.05). Ratios of the diameters of fetal cardiac structures were calculated in order to identify for differential changes in the growth of structures.
Conclusions: The presented data derived from 4396 normal fetuses provide the reference values of fetal echocardiography in China, which provide guidance to fetal echocardiography examinations.